Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


A new form of glass through molecular entanglement


Physicists at the University of Vienna in collaboration with the Max Planck Institute for Polymer Research have discovered a new type of glass formed by long, cyclic molecules. The scientists successfully demonstrated that by making parts of the rings more mobile, the rings become more strongly entangled and the molecular fluid glassifies. The novel “active topological glass” is presented in the latest issue of Nature Communications.

Glass materials are ubiquitous in everyday life, ranging from window panes to porcelain espresso cups. Even PET plastic bottles, made of long polymeric molecules, are considered a form of glass. All these examples are produced by rapid cooling of a melt of particles, such as silica in case of windows or polymers in plastic bottles.

Ring molecules (differentiated by colors) exhibit mutual threadings that inhibits their motion and renders the glass.

University of Vienna / MPI-P

To visualise and quantify the threadings we computationally spanned a triangulated minimal surface (bubble) on each ring molecule (here the contour of a surface).

University of Vienna / MPI-P

Their unique properties, such as transparency or tensile strength arise from their microscopic disordered and tightly packed structure. While melted, the particles can move easily past each other or be rearranged by external forces as in glass blowing.

However, when cooled down each particle becomes caged by its neighbours rendering the glass solid and resistant to deformation.

About twenty-five years ago, scientists conjectured that yet a new form of glass could exist if the constituent particles are long, flexible and, importantly, cyclic molecules. Such "rings" can thread each other, meaning one ring piercing through the eye of another ring, by which constraining each other’s motion.

If many rings are threaded, for one of them to move away a number of other rings must un-thread sequentially to set it free. This takes very long to happen by random thermal fluctuations and therefore the conjectured disordered structure behaves effectively as a solid glass.

In contrast to the hypothesis, such a glassy state of ring polymers has not been observed in experiments, possibly due to limited length of the ring polymers that is currently possible to synthesize. In computer simulations, the glass could be induced only by artificially immobilizing a fraction of all the rings in space.

Then, naturally, the other rings threaded by the immobile ones could not move. Although appealing, the imposed immobilizing is unlikely to be achieved in practice. It seemed that a real "topological glass", a glass formed by strongly entangled cyclic molecules, remains elusive.

"We have taken the opposite approach to what has been attempted so far to find a topological glass. Rather than the nonphysical immobilizing of rings, in our simulations we made rings' segments more mobile. We achieve this by forcing parts of the rings to fluctuate more strongly", explains Iurii Chubak, together with Jan Smrek joint first authors from the University of Vienna.

"The stronger-than-thermal fluctuations can be realized by incorporating molecular motors, molecules which locally exert forces on the expense of energy. Another option is the synthesis of rings containing segments with enhanced light absorption. Such actively driven rings then thread and entangle so extensively that they practically cannot move past each other. Remarkably, we observe the topological glass at experimentally accessible ring lengths and driving forces", says Jan Smrek, which carried out its work in cooperation with the Max Planck Institute for Polymer Research in Mainz and with support from the Lise Meitner Programme of the Austrian Science Fund FWF.

"This glass is microscopically very distinct from the material of the bottle you typically drink your favorite beverage from. More detailed properties of the active topological glass remain to be uncovered. However, it is already exciting. Not only from the fundamental physics point of view, but also due to the potential applications such as creating a fluid material with reversible vitrification upon light exposure", adds senior author Christos Likos from the Faculty of Physics.

Interestingly, the same basic physical ingredients as in the present active topological glass are found also in the nuclei of living eukaryotic cells. Indeed, the DNA fibers are long uncrossable polymers at high density with active driving due to various molecular motors. "We are aware of the similarities of our simulated system to the nuclei of living cells. However, if the DNA under living conditions could be in the state of the active topological glass, remains an open question", concludes Jan Smrek.

Wissenschaftliche Ansprechpartner:

Prof. Dr. Kurt Kremer
Tel.: +49 6131 379-141


Active topological glass
Jan Smrek, Iurii Chubak, Christos N. Likos & Kurt Kremer
Nature Communications volume 11, Article number: 26 (2020)

Dr. Christian Schneider | Max-Planck-Institut für Polymerforschung
Further information:

More articles from Physics and Astronomy:

nachricht Scientists see energy gap modulations in a cuprate superconductor
02.04.2020 | DOE/Brookhaven National Laboratory

nachricht BESSY II: Ultra-fast switching of helicity of circularly polarized light pulses
02.04.2020 | Helmholtz-Zentrum Berlin für Materialien und Energie

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Harnessing the rain for hydrovoltaics

Drops of water falling on or sliding over surfaces may leave behind traces of electrical charge, causing the drops to charge themselves. Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz have now begun a detailed investigation into this phenomenon that accompanies us in every-day life. They developed a method to quantify the charge generation and additionally created a theoretical model to aid understanding. According to the scientists, the observed effect could be a source of generated power and an important building block for understanding frictional electricity.

Water drops sliding over non-conducting surfaces can be found everywhere in our lives: From the dripping of a coffee machine, to a rinse in the shower, to an...

Im Focus: A sensational discovery: Traces of rainforests in West Antarctica

90 million-year-old forest soil provides unexpected evidence for exceptionally warm climate near the South Pole in the Cretaceous

An international team of researchers led by geoscientists from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) have now...

Im Focus: Blocking the Iron Transport Could Stop Tuberculosis

The bacteria that cause tuberculosis need iron to survive. Researchers at the University of Zurich have now solved the first detailed structure of the transport protein responsible for the iron supply. When the iron transport into the bacteria is inhibited, the pathogen can no longer grow. This opens novel ways to develop targeted tuberculosis drugs.

One of the most devastating pathogens that lives inside human cells is Mycobacterium tuberculosis, the bacillus that causes tuberculosis. According to the...

Im Focus: Physicist from Hannover Develops New Photon Source for Tap-proof Communication

An international team with the participation of Prof. Dr. Michael Kues from the Cluster of Excellence PhoenixD at Leibniz University Hannover has developed a new method for generating quantum-entangled photons in a spectral range of light that was previously inaccessible. The discovery can make the encryption of satellite-based communications much more secure in the future.

A 15-member research team from the UK, Germany and Japan has developed a new method for generating and detecting quantum-entangled photons at a wavelength of...

Im Focus: Junior scientists at the University of Rostock invent a funnel for light

Together with their colleagues from the University of Würzburg, physicists from the group of Professor Alexander Szameit at the University of Rostock have devised a “funnel” for photons. Their discovery was recently published in the renowned journal Science and holds great promise for novel ultra-sensitive detectors as well as innovative applications in telecommunications and information processing.

The quantum-optical properties of light and its interaction with matter has fascinated the Rostock professor Alexander Szameit since College.

All Focus news of the innovation-report >>>



Industry & Economy
Event News

13th AKL – International Laser Technology Congress: May 4–6, 2022 in Aachen – Laser Technology Live already this year!

02.04.2020 | Event News

“4th Hybrid Materials and Structures 2020” takes place over the internet

26.03.2020 | Event News

Most significant international Learning Analytics conference will take place – fully online

23.03.2020 | Event News

Latest News

Capturing 3D microstructures in real time

03.04.2020 | Materials Sciences

First SARS-CoV-2 genomes in Austria openly available

03.04.2020 | Life Sciences

Do urban fish exhibit impaired sleep? Light pollution suppresses melatonin production in European perch

03.04.2020 | Life Sciences

Science & Research
Overview of more VideoLinks >>>